Download - Energy
Transcript
Energy
Review & Continuation
Forms of Energy
• Potential– Chemical– Gravitational– Nuclear– Mechanical
• Kinetic– Motion– Sound– Thermal– Radiant– Electrical
Formulas
• F=ma• W=Fd <<or>> W=mad• P=W/t <<or>> P=mad/t• PE=mgh• KE=1/2mv2
An Example
Mass= 10 kg
Height= 1 m
Gravity=9.8m/s/s
PE=mghPE=(10)(9.8)(1)PE=98 Joules
An Example
Mass= 10 kg
Height= 0.5m
Gravity=9.8m/s/s
PE=mghPE=(10)(9.8)(0.5)
PE=49 Joules
Conservation of Energy
• 1st Law of Thermodynamics– Energy cannot be created or destroyed
• If the distance changed from 1m to 0.5m, the amount of PE decreased from 98 to 49
• Where did the energy go?– It was converted from PE to KE!